Cyclopentanone derivatives, odoriferous compositions containing them and process of preparation thereof

ABSTRACT

Novel cyclopentanone derivatives are disclosed having the formula ##SPC1## 
     In which R represents a hydrocarbon group of 3 to 7 carbon atoms, X represents a cyano, formyl, hydroxymethyl, lower alkoxymethyl, lower alkanoyloxymethyl or lower alkylcarbonyl group and Y represents an oxo or ketal group, 
     With the proviso that R does not represent an n-pentyl group when, simultaneously, X represents a methylcarbonyl group and Y represents an oxo group. 
     Processes for the preparation of the said cyclopentanone derivatives and also the use thereof in perfumes, cosmetic and other products are disclosed.

This application is a continuation-in-part of application Ser. No. 322,747, filed Jan. 11, 1973 now U.S. Pat. No. 3,951,876.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to novel cyclopentanone derivatives and to processess for their preparation,

The cyclopentanone derivatives according to the invention have the formula ##SPC2##

Wherein R represents a hydrocarbon group having from 3 to 7 carbon atoms. X represents a cyano, formyl, hydroxymethyl, lower alkoxymethyl, lower alkanoyloxymethyl or lower alkylcarbonyl group and Y represents an oxo or ketal group, with the proviso that R does not represent an n-pentyl group when, simultaneously, X represents an acetyl group and Y represents an oxo group.

R may represent a saturated or unsaturated, aliphatic, aromatic or araliphatic hydrocarbon group, which may be a straight chain group, a branched chain or a cyclic group. R may thus, for example, represent an alkyl, alkenyl, aryl, aralkyl, cycloalkyl or cycloalkyl-alkyl group. Specific examples of such groups include n-propyl, isopropyl, n-butyl, sec. butyl, tert. butyl, n-pentyl, isopentyl or a hexyl or heptyl group, or a corresponding ethylenically unsaturated group, cyclopentyl, cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl, cyclopropylethyl, phenyl or benzyl.

Where R contains a cyclic moiety it is preferred that the cyclic moiety be linked to the cyclopentanone nucleus via a methyl or ethyl linkage.

Especially preferred compounds, according to this invention, are those in which R represents an n-pentyl group inasmuch as these compounds have particularly remarkable odoriferous properties.

The lower alkyl and lower alkoxy groups as well as the alkyl moiety of the lower alkanoyl groups in the substituent X are defined as being such groups containing from 1 to 6 carbon atoms in the alkyl moiety. Examples of such alkyl moieties include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, n-pentyl and n-hexyl.

The ketal group may be a cyclic ketal group containing 2 or 3 carbon atoms or a di-lower alkoxy group in which the lower alkoxy groups each contain up to 4 carbon atoms. The compounds in which Y represents a ketal group may thus be represented by the formula: ##SPC3##

in which R and X have the meanings given above and R¹ and R² each represent a lower alkyl group containing up to 4 carbonatoms, or R¹ and R² taken together represent a lower alkylene group having 2 or 3 carbon atoms. R¹ and R² preferably represent methyl or ethyl groups or, when taken together, an ethylene group.

Examples of compounds according to the present invention include: 3-cyanomethyl-2-n-pentyl-1-cyclopentanone; 3-cyanomethyl-2-isopropyl-1-cyclopentanone; 3-cyanomethyl-2-(2-n-hexenyl)-1-cyclopentanone; 3-cyanomethyl-1,1-ethylenedioxy-2 -n-pentyl-cyclopentane; 3-cyanomethyl-2-cyclopentylmethyl-1,1-ethylenedioxy-cyclopentane; 3-formylmethyl-2-n-butyl-1-cyclopentanone; 3-formylmethyl-2-n-pentyl-1-cyclopentanone; 3-formylmethyl-2-benzyl-1-cyclopentanone; 2-cyclopentylmethyl-3 -formylmethyl-1-cyclopentanone; 1,1-ethylenedioxy-3-formylmethyl-2-isopropyl-cyclopentane; 1,1-ethylenedioxy-3-formylmethyl-2-n-pentyl-cyclopentane; 3-hydroxyethyl-2-n-pentyl-1-cyclopentanone; 3-hydroxyethyl-2-(2-n-pentenyl)-1-cyclopentanone; 2-cyclopropylethyl-3-hydroxyethyl-1-cyclopentanone; 1,1-ethylenedioxy-3-hydroxyethyl-2-n-pentyl-cyclopentane; 2-cyclohexylmethyl-1,1-ethylenedioxy-3-hydroxyethylcyclopentane; 2-(cyclopropyl-n-propyl)-1,1-ethylenedioxy-3-hydroxymethylcyclopentane; 2-cyclohexylmethyl-3-methoxyethyl-1-cyclopentanone; 2-n-pentyl-3-n-propoxymethyl-1-cyclopentanone; 2-(2-n-butenyl)-3-n-hexyloxymethyl-1-cyclopentanone; 1,1-ethylenedioxy-2-n-pentyl- 3-n-pentyloxymethyl-cyclopentane; 1,1-ethylenedioxy- 2-n-pentyl-3-n-propionyloxymethyl-cyclopentane; 1,1-ethylenedioxy-3-isopentanoyloxymethyl-2-isopentylcyclopentane; 3-acetoxyethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane; 3-acetyloxymethyl-1,1-ethylenedioxy-2-n-hexyl-cyclopentane; 3-acetoxyethyl-2-n-pentyl-1-cyclopentanone; 2-n-pentyl-3-n-propionyloxymethyl-1-cyclopentanone; 2-n-pentyl-3-propionylmethyl-1-cyclopentanone; 3-acetylmethyl-2-n-butyl-1-cyclopentanone; 3-acetylmethyl-2-(2-n-hexenyl)-1-cyclopentanone; 3-n-hexanoylmethyl-2-n-pentyl-1-cyclopentanone; 3-acetylmethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane; 1,1-ethylenedioxy-3-isobutyrylmethyl-2-n-pentyl-cyclopentane; [2-(cis-2-n-pentyl)- 3-(2-oxopropyl)-1-cyclopentanone; 1,1-ethylenedioxy-3-formylmethyl-2-(cis-2-n-pentenyl)-cyclopentane; 3-formyl-2-(cis-2-n-pentenyl)-1-cyclopentanone; and 3-hydroxyethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone.]

The compounds according to the present invention can be prepared by various processes. Thus, the compounds according to the invention having the formula: ##SPC4##

wherein R has the meaning given above, may be prepared by hydrolysing and decarboxylating a compound having the formula: ##SPC5##

in which R has the meanings given above and R³ represents a lower alkyl group having from 1 to 4 carbon atoms, preferably methyl or ethyl.

The compounds of the invention of formula I in which R, X and Y have the meanings given above, as qualified by the proviso, with the exception of those compounds in which X represents a lower alkylcarbonyl group, may all be prepared by the processess using the 3-cyanomethyl compound of formula III as starting material. The compounds of formula I may be prepared by a process which involves firstly ketalising the compound of formula III in order to obtain the corresponding ketal having the formula ##SPC6##

in which R, R¹ and R² have the meanings given above, followed by reduction of the cyano group and if desired, elimination of the ketal group in order to regenerate the 1-keto group.

The ketals of formula V may be prepared by ketalisation processes: for example the cyclic ketals may be prepared by treating the corresponding ketone with a lower alkylene glycol such as ethylene glycol or propylene glycol or with a mixed orthoformate of a lower alkyl ehtylene glycol in the presence of an acid catalyst. The di-lower alkoxy ketals may be prepared by reacting the corresponding ketone with a lower alkyl orthoformate in the presence of an acid catalyst.

The reaction conditions and the reactants utilised to effect the reduction of the cyano group depend on the compound to be prepared. For the preparation of compounds in which X represents a formyl group, the reduction can be effected with the aid of diisobutyl aluminium hydride, to obtain compounds having the formula: ##SPC7##

in which R, R¹ and R² have the meanings given above.

The compounds of formula VI can either be further reduced in order to obtain a corresponding 3-hydroxyethyl compound or the ketal group may be eliminated at this stage, in order to obtain a compound having the formula: ##SPC8##

in which R has the meanings given above.

The reduction of the 3-formylmethyl compounds of formula VI to give the corresponding 3-hydroxyethyl compounds corresponding to formula VIII may be effected, for example, by the use of a complex of diisobutylaluminium hydride with pyridine, lithium aluminium hydride orisopropyl alcohol in the presence of aluminium isopropylate.

The resulting compounds having the formula: ##SPC9##

in which R, R¹ and R² have the meanings given above.

may then be either esterified or etherified to give the corresponding compounds of formula I in which X represents a lower alkoxymethyl or lower alkanoyloxymethyl group and R has the meanings given above, or the ketal group may be eliminated to give compounds having the formula: ##SPC10##

in which R has the meanings given above.

The etherification or esterification reactions to give compounds of formula: ##SPC11##

wherein Z represents a lower alkyl or lower alkylcarbonyl group in which the alkyl groups and moieties contain from 1 to 6 carbon atoms, and R, R¹ and R² have the meanings given above,

may be effected followed if desired by elimination of the ketal group to give the corresponding 1-oxo compounds of formula: ##SPC12##

in which R and Z have the meanings given above.

In all of the processess involving the replacement of the ketal group by the 1-oxo group, the reaction may be effected, for example, by heating in the presence of excess acetone, and preferably, in the presence of an acid catalyst such as p-toluenesulphonic acid.

The compounds according to the present invention having the formula: ##SPC13##

wherein R⁴ represents a lower alkyl group having from 1 to 6 carbon atoms and R has the meaning given above,

with the proviso that R does not represent an n-pentyl group when R⁴ represents methyl, may conveniently be prepared by hydrolysis and decarboxylation of a compound of formula: ##SPC14##

wherein R and R⁴ have the meanings given in the preceding paragraph and R⁵ represents a lower alkyl group having from 1 to 4 carbon atoms, preferably methyl or ethyl.

The hydrolysis and decarboxylation may be effected by any convenient method. One convenient process comprises effecting the reaction with water, under pressure and in a medium which is initially substantially neutral. This reaction is conveniently effected at a temperature of from 120° to 300°C and, preferably, from 140° to 250°C. It is preferred to effect the reaction using the same weight of water and starting material. Under normal conditions, the reaction is effected in an autoclave which has been previously purged of air.

The starting material of formula IV may be prepared in convenient manner by condensing a cyclopent-2-en-1-one having a hydrocarbon group in position 2 with a lower alkyl cyanoacetate.

The starting material of formula XIII may conveniently be prepared from a cyclopent-2-en-1-one having a hydrocarbon group in position 2, by condensation thereof with an alkyl acyl acetate having the formula: ##EQU1## in which R⁴ and R⁵ have the meanings given above.

Also according to the present invention these are produced intermediates having the formula IV, which are useful for the preparation of 3-cyanomethyl compounds of formula III as defined above.

Further according to the present invention there are provided intermediates having the formula XIII which are useful for the preparation of compounds of formula XII as defined above.

The compounds according to the present invention having the formula: ##SPC15##

in which R⁶ represents hydrogen, a lower alkyl group of 1 to 6 carbon atoms or a lower alkylcarbonyl group in which the alkyl fraction has 1 to 6 carbon atoms, and R¹ and R² are as defined in formula V,

can be prepared by reducing a compound of the formula: ##SPC16##

to yield the corresponding 3-hydroxyethyl compound, of the formula: ##SPC17##

and subsequently if desired etherifying or esterifying the compound of formula VIII so obtained to yield a compound of the formula: ##SPC18##

in which Z represents a lower alkyl group of 1 to 6 carbon atoms or a lower alkanoylcarbonyl group in which the alkyl moiety contains from 1 to 4 carbon atoms and R, R¹ and R² have the aforesaid significances.

The compounds of the present invention having the formula: ##SPC19##

in which R represents a hydrocarbon group of 3 to 7 carbon atoms and R⁷ represents a formyl, hydroxymethyl, lower alkoxymethyl or lower alkanoyloxymethyl group in which the alkyl moieties contain 1 to 6 carbon atoms,

can be prepared by treating a compound of the formula: ##SPC20##

in which R and R⁷ have the aforesaid meanings and R¹ and R² are as defined in formula V,

with an excess of a lower dialkylketone in the presence of an acid catalyst.

The compounds according to the present invention having the formula: ##SPC21##

in which R⁴ represents a lower alkyl group of 1 to 6 carbon atoms and R represents a hydrocarbon group of 3 to 7 carbon atoms,

with the proviso that R does not represent an n-pentyl group when R⁴ represents a methyl group can be prepared by hydrolysing and decarboxylating a compound of the formula: ##SPC22##

in which R and R⁴ have the aforesaid meanings, as qualified by the aforesaid proviso, and R⁵ represents a lower alkyl group of 1 to 4 carbon atoms.

The cyclopentanone derivatives of the present invention have valuable odorant properties. In general, the predominant odorant note of the compounds is a floral note. The odours of the free ketones are generally more pronounced than those of the ketals from which they are derived. Considered individually, certain compounds according to the invention present a variety of other interesting notes, for example green, fruity notes as well as the odour of newly woven fabric. Thus, for example, 3-acetoxyethyl-2-n-pentyl-cyclopentanone possesses floral and fruity notes, 3-formylethyl-2-n-pentyl-cyclopentanone possesses floral and green notes and an odour reminiscent of lilies, 3-hydroxyethyl-2-n-pentyl-cyclopentanone has a very delicate floral odour reminiscent of lily of the valley and of cyclamen, 3-cyanomethyl-2-n-pentyl-cyclopentanone has a floral odour of the jasmin type, 1,1-ethylenedioxy-3-formyl-2-n-pentyl-cyclopentane has an odour of bitter oranges, and 3-cyanomethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane has a floral odour.

The compounds according to the invention may be used in perfume concentrates and perfumed products in any desired combination, depending on the intensity of the floral and other notes required. In perfumes, they may conveniently be used in a proportion of up to 20%, for example 0.5 to 20%, by weight. The compounds can be used alone, or more preferably with other odorant substances, diluents and conventional fixatives for perfuming eau de cologne, toilet waters, washing agents, aerosol and soap compositions, etc.

The invention will now be illustrated with reference to the following Examples.

EXAMPLE 1

Into a 6 liter reactor provided with a stirrer, a dropping funnel and a vent are introduced 760 g of 2-n-pentylcyclopent-2-en-1-one, 1130 g of ethyl cyanoacetate and 625 g of absolute tertiary amyl alcohol. After 1 hour, 560 ml of a 1.78 N toluene solution of sodium tert. amylate are introduced whilst maintaining the temperature between 19° and 29°C. The mixture is then left for 16 hours at ambient temperature. The mass is then cooled to -5°C and neutralised with 5% aqueous sulphuric acid solution. The reaction product is decanted and extracted with toluene; the toluene solutions are washed to neutrality and distilled. There is thus obtained 1850 g of crude product which is rectified under reduced pressure to give 1116 g of pure 3-carbethoxycyanomethyl-2-n-pentyl-1-cyclopentanone. This represents a yield of 84.2% (without taking into account the 2-n-pentyl-cyclopent-2-en-1-one recovered). The product shows the following constants: b.p.₀.3 = 155° - 157°C, n_(D) ¹⁵ = 1.4686. The principal bands of its infra-red spectrum are as follows:

    ______________________________________                                         2250 cm.sup.-.sup.1                                                                         υ(C=N): saturated nitrile                                 1740 cm.sup.-.sup.1 (broad)                                                                 υ(C=O): saturated ester +                                              cyclopentanone                                                    1405 cm.sup.-.sup.1                                                                         δ(CH.sub.2): α to the carbonyl group                  1250 and 1190 cm.sup.-.sup.1                                                                ν(C--O): in the ester group                                     720 cm.sup.-.sup.1                                                                         ρ(CH.sub.2).sub.n : in the n-pentyl group                     ______________________________________                                    

Examination of the N.M.R. spectrum of the product indicates the presence of a mixture due to 3 centres of asymmetry. The CH₂ of the ethyl group is exhibited in the form of 3 quadruplets and the H α to the CO in the form of 2 doublets.

EXAMPLE 2

Into a 10 liter autoclave are introduced 1113 g of 3-carbethoxycyanomethyl-2-n-pentyl-1-cyclopentanone, 2184 ml of water, 67.2 ml of pyridine and 4.2 g of copper powder. The autoclave is closed, a vacuum created therein (20 mm) and then heated with mechanical stirring for 21/2 hours. After 11/2 hours, the temperature of the mass is 195°C and the interior pressure of the autoclave is 22 kg/cm². After cooling, extraction, washing and distillation of solvent, there are obtained 734 g of crude product which on rectification yields: 320 g of 2-n-pentyl-cyclopent-2-en-1-one, followed by 323 g of 3-cyanomethyl-2-n-pentyl-1-cyclopentanone.

The transformation rate of the reaction is consequently 68.8%. The product exhibits the following constants: b.p.₀.4 = 122° - 125°C, n_(D) ¹⁵ = 1.4700.

    ______________________________________                                         The infra-red spectrum                                                                        principal bands at:                                             ______________________________________                                         2240 cm.sup.-.sup.1                                                                           υ(C=N): saturated nitrile                               1740 cm.sup.-.sup.1                                                                           υ(C=O): cyclopentanone                                  1405 cm.sup.-.sup.1                                                                           δ(CH.sub.2): α to the carbonyl group                1420 cm.sup.-.sup.1                                                                           δ(CH.sub.2): α to the nitrile group                  720 cm.sup.-.sup.1                                                                           ρ(CH.sub.2).sub.n : pentyl group                            1150 cm.sup.-.sup.1 strong band.                                               ______________________________________                                    

With respect to the N.M.R. spectrum, apart from the triplet at δ = 0.88 p.p.m. due to the methyl group on the end of the chain, the rest of the spectrum cannot be analysed because of the presence of a mixture of two epimers.

EXAMPLE 3

Into a 2 liter flask fitted with a 1 meter adiabatic column provided with a metallic lining, are placed: 400 g of 3-cyanomethyl-2-n-pentyl-1-cyclopentanone, 522 g of the glycoketal of methylethyl ketone and 4.5 g of paratoluenesulphonic acid. The mass is progressively heated in order to slowly distil the methyl ethyl ketone from the head of the column (temperature of the mass 128°-132°C; temperature of the vapour 80°C). The operation lasts about 5 hours. Then the excess glycoketal of methylethyl ketone is removed (temperature of the mass 132°-135°C; temperature of the vapour 110°-112°C). The mass is then cooled, 30 g of dry sodium carbonate added thereto, stirred for a half-hour and the mass washed to neutrality after diluting with 200 ml of ethyl ether. After distillation of the solvent and rectification of the crude product, there is obtained 360 g of 3-cyanomethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane, which represents a yield of 73.4%. The product exhibits the following constants: b.p.₀.5 = 136°-138°C, n_(D) ¹⁵ = 1.4724.

    ______________________________________                                         The infra-red spectrum                                                                           principal bands at:                                          ______________________________________                                         2250 cm.sup.-.sup.1                                                                              υ(C=N): saturated nitrile                            1420 cm.sup.-.sup.1                                                                              δ(CH.sub.2): α to the nitrile group              1150, 1115 and 1040 cm.sup.-.sup.1                                                               υ(C--O): glycoketal.                                 ______________________________________                                    

The N.M.R. shows a triplet at δ = 0.89 p.p.m. due to CH₃ at the end of the chain and a double AB centre at 3.83 p.p.m. due to O--CH₂ --CH₂ --O. The rest of the spectrum indicates that a mixture of two epimers is present.

EXAMPLE 4

Into a 5 liter flask fitted with a stirrer, dropping funnel and vent, are introduced 358.6 g of 3-cyanomethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane dissolved in 755 ml of anhydrous petroleum ether. There is then added over 1 hour a solution of 280 g of diisobutylaluminium hydride in 755 ml of anhydrous petroleum ether, while maintaining the temperature between 25° and 30°C. After addition of the hydride, the temperature of the mass is held at 30°C for 2 hours and it is then diluted with 1500 ml of technical petroleum ether. The whole of the solution is then added over one hour to 850 ml of a 10% aqueous solution of ammonium chloride while keeping the temperature in the region of 0°C. Into the so obtained mass, there is finally added, with constant stirring a solution of 396 g acetic acid in 3300 ml of water. The petroleum-ether solutions are decanted, washed to neutrality and distilled; they yield 345 g of crude product which is rectified under 1 mm Hg. There is thus obtained 250 g of 1,1-ethylenedioxy-3-formylmethyl-2-n-pentyl-cyclopentane, which represents a yield of 69%. The product exhibits the following constants: b.p.₁.0 = 120°-124°C, n_(D) ¹⁵ = 1.4715.

    ______________________________________                                         The infra-red spectrum has principal bands at:                                 ______________________________________                                         2710 cm.sup.-.sup.1                                                                             υ(C--H): saturated aldehyde                           1722 cm.sup.-.sup.1                                                                             υ(C=O): saturated aldehyde                            1150, 1118 and 1028 cm.sup.-.sup.1                                                              υ(C--O): glycoketal                                    720 cm.sup.-.sup.1                                                                             ρ(CH.sub.2).sub.n : pentane chain.                        ______________________________________                                    

The N.M.R. spectrum exhibits a triplet at δ = 0.86 p.p.m. (CH₃ at the end of the chain), a spectral AB centre at 3.88 p.p.m. (4 H: dioxolane), a triplet (1 H) centre at 9.66 p.p.m. (--CH₂ --CHO).

EXAMPLE 5

A mixture of 24 g of 1,1-ethylenedioxy-3-formylmethyl-2-n-pentyl-cyclopentane, 40 ml of dioxane, 32 ml of water and 0.18 g paratoluenesulphonic acid is refluxed for 3 hours. It is then cooled, 120 ml of water added and extracted three times with 100 ml of benzene. The benzene solutions are washed to neutrality and concentrated under reduced pressure. There are obtained 22 g of crude product which are rectified and which yield 15.5 g of product; b.p.₁.0 = 110°-140°C. The distillate is a mixture of keto aldehyde and the dioxolane of the aldehyde function (3-ethylenedioxymethyl-2-n-pentyl-1-cyclopentanone) in the proportions of 75/25. By careful rectification of this mixture, there is obtained 11 g of pure 3-formylmethyl-2-n-pentyl-1-cyclopentanone exhibiting: b.p.₀.5 = 90°C, n_(D) ¹⁵ = 1.4688.

    ______________________________________                                         The infra-red spectrum has principal bands at:                                 ______________________________________                                         2730 cm.sup.-.sup.1                                                                            υ(CH): aldehyde                                        1725 cm.sup.-.sup.1                                                                            υ(C=O): saturated aldehyde                             1740 cm.sup.-.sup.1                                                                            υ(C=O): cyclopentanone                                 1410 cm.sup.-.sup.1                                                                            δ(CH.sub.1): α to the carbonyl                      720 cm.sup.-.sup.1                                                                            ρ(CH.sub.2).sub.4                                          ______________________________________                                          The N.M.R. spectrum exhibits:                                                  0.87 p.p.m. triplet due to CH.sub.3 at the end of the chain                    9.75 p.p.m. triplet due to the aldehyde proton (triplet complex arises         from the fact that there is present a mixture of epimers).               

EXAMPLE 6

Into a 1 liter flask equipped as described in Example 1, are introduced: 42.6 g of diisobutylaluminium hydride dissolved in 100 ml of anhydrous benzene. Maintaining the temperature in the region of 0°C, 24 g pyridine is added thereto over 20 min. Still at the same temperature there is then added 60 g of 1,1-ethylenedioxy-3-formylmethyl-2-n-pentylcyclopentane dissolved in 125 ml of anhydrous benzene over 30 minutes. The reaction mass is then brought to 30°C and held at that temperature for 2 hours; it is then diluted with 250 ml benzene, cooled to 0°C and then poured into 135 ml of an iced 10% aqueous solution of ammonium chloride. A solution of 60 g acetic acid in 500 ml of water is then added. The benzene solutions are decanted, washed to neutrality and distilled. The crude product so obtained is rectified under 0.5 mm Hg. There is thus obtained 46 g of 1,1-ethylenedioxy-3-hydroxyethyl-2-n-pentyl-cyclopentane, which represents a yield of 76%. The product has the following constants: b.p.₀.5 = 122°-124°C, n_(D) ¹⁵ = 1.4775.

    ______________________________________                                         The infra-red spectrum has principal bands at:                                 ______________________________________                                         3400 cm.sup.-.sup.1                                                                          υ(OH): associated alcohol                                              function                                                         1150 and 1115 cm.sup.-.sup.1                                                                 υ(C--O): glycoketal                                      1035 cm.sup.-.sup.1                                                                          υ(C--O): primary alcohol (very                                         strong band)                                                      720 cm.sup.-.sup.1                                                                          ρ(CH.sub.2).sub.n : pentane chain.                           ______________________________________                                    

EXAMPLE 7

20.6 g of 1,1-ethylenedioxy-3-hydroxyethyl-2-n-pentylcyclopentane are mixed with 50 g of acetone and 0.162 g of paratoluenesulphonic acid. The mixture is brought to reflux during 1 hour, 0.26 ml of triethanolamine are then added thereto, the mixture concentrated on a water-bath under 25 mm Hg and the mass dissolved in 100 ml of benzene. The benzene solution, washed to neutrality and distilled under reduced pressure, yields 22 g of crude product which is rectified. There are thus obtained 15 g of 3-hydroxyethyl-2-n-pentylcyclopentanone which represents a yield of 89%. The product has the following constants: b.p.₀.5 = 112°-115°C, n_(D) ¹⁵ = 1.4740.

    ______________________________________                                         The infra-red spectrum has principal bands at:                                 ______________________________________                                         3440 cm.sup.-.sup.1                                                                      υ(OH): associated alcohol functions                          1740 cm.sup.-.sup.1                                                                      υ(C=O): cyclopentanone                                       1410 cm.sup.-.sup.1                                                                      δ(CH.sub.2): α to the carbonyl group                     1050 cm.sup.-.sup.1                                                                      υ(C--O): primary alcohol function                             720 cm.sup.-.sup.1                                                                      δ(CH.sub.2).sub.n : pentane chain.                             ______________________________________                                    

EXAMPLE 8

1,1-Ethylenedioxy-3-hydroxyethyl-2-n-pentyl-cyclopentane (18.2 g) is mixed with 11.5 g acetic anhydride dissolved in 15 g of pyridine. The homogeneous mixture is left at ambient temperature for 15 hours and then brought during 1 hour to 95°C. 65 ml of water are then added and the mixture is stirred for 30 minutes at 95°C. After cooling, the mixture is extracted 3 times with 50 ml of benzene. The benzene solutions are washed to neutrality and concentrated under reduced pressure yielding 22 g of crude product which are rectified. There are thus obtained 19.9 g of 3-acetoxyethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane (97.5% yield) exhibiting: b.p.₀.5 = 120°-125°C, n_(D) ¹⁵ = 1.4648.

    ______________________________________                                         The infra-red spectrum has principal bands at:                                 ______________________________________                                         1740 cm.sup.-.sup.1                                                                            υ(C=O): saturated ester                                1360 cm.sup.-.sup.1                                                                            δ(CH.sub.3): in --CO--CH.sub.3                           1240 cm.sup.-.sup.1                                                                            υ(C--O): acetate                                       1150, 1120 and 1040 cm.sup.-.sup.1                                                             ethylene-ketal                                                  730 cm.sup.-.sup.1                                                                            ρ(CH.sub.2).sub.n                                          ______________________________________                                          The N.M.R. spectrum exhibits:                                                  0.88 p.p.m. triplet CH.sub.3 at the end of the chain                           1.95 p.p.m. singlet --CO--CH.sub.3                                             3.80 p.p.m. triplet --CH.sub.2 --CH.sub.2 --OAc                          

EXAMPLE 9

A mixture of 7.1 g of 2-acetoxyethyl-1,1-ethylenedioxy-2-n-pentyl-cyclopentane, 14.5 g of acetone and 0.0475 g of paratoluenesulphonic acid is brought to reflux during 1 hour. There is added thereto 0.08 mole of triethanolamine and the mixture is concentrated under reduced pressure on a water-bath. The residue is dissolved in 50 ml of benzene and washed with water until neutral. The distilled benzene solution yields 7 g of crude product which are rectified. There are obtained 5 g of 3-acetoxyethyl-2-n-pentyl-1-cyclopentanone (83.3% yield) having: b.p.₀.5 = 110°-113°C, n_(D) ¹⁵ = 1.4610.

    ______________________________________                                         The infra-red spectrum has principle bands at:                                 ______________________________________                                         1740 cm.sup.-.sup.1                                                                          υ(C=O): saturated ester plus                                           cyclopentanone                                                   1410 cm.sup.-.sup.1                                                                          δ(CH.sub.2): α to a carbonyl                         1240 cm.sup.-.sup.1                                                                          υ(C--O): acetate                                          725 cm.sup.-.sup.1                                                                          ρ(CH.sub.2).sub.n                                            ______________________________________                                          The N.M.R. spectrum exhibits:                                                  0.88 p.p.m. triplet CH.sub.3 at the end of the chain                           1.98 p.p.m. singlet --CO--CH.sub.3                                             4.10 p.p.m. triplet --CH.sub.2 --CH.sub.2 --OAc                          

EXAMPLE 10

Into a 2 liter glass flask equipped as in Example 1, are added 152 g of 2-n-pentyl-cyclopent-2-en-1-one and 216 g of ethyl propionylacetate. Then, maintaining the temperature at 20°C, there are added over 1 hour 250 g of a 22% solution of sodium tert. amylate in toluene and then 125 g of anhydrous tertiary amyl alcohol. The temperature is then brought to 35°C and maintained for 24 hours, then the mixture is neutralised with 500 g of a 5% aqueous solution of sulphuric acid. The aqueous phase is extracted twice with 50 ml of toluene. The toluene solutions are combined, washed to neutrality and distilled. By rectification of the residue there are obtained: 90 g of pentylcyclopentanone, 132 g of ethyl propionylacetate and a residue of 120 g. The latter, subjected to a molecular distillation (1/100 mm Hg) yields 112 g of diketoester [2-n-pentyl-3-(1-carbethoxy-2-oxo-n-butyl)-1 -cyclopentanone], which represents a yield of 92% in relation to pentylcyclopentenone actually used.

The product had the following physical constants: n_(D) ²⁰ = 1.4658 d₄ ²⁰ = 1.0275.

EXAMPLE 11

Into a 1 liter autoclave, there are introduced: 187 g of 2-n-pentyl-3-(1-carbethoxy-propionylmethyl)-1-cyclopentanone and 187 g of distilled water. The autoclave is evacuated and rapidly heated to 140°C, which temperature is maintained for 3 hours. After cooling and decompression, the mass is extracted with benzene. The benzene solutions are washed with water and distilled; there are thus obtained 3 g of pentylcyclopentanone and 132 g of 2-n-pentyl-3-propionylmethyl-1-cyclopentanone, which represent a yield of 82.5% in relation to the diketoester actually used up. The product has the following physical constants: b.p.₁ = 126°C; n_(D) ²⁰ = 1.4692; d₄ ²⁰ = 0.9525.

EXAMPLE 12

Into a 6 liter reactor provided with a stirrer, a dropping funnel and a vent are introduced 408 g of 2-(cis-2-n-pentenyl)-cyclopent-2-en-1-one, 765 g of ethyl cyanoacetate and 425 g of absolute tertiary amyl alcohol. After one hour, 380 ml of a 1.78 N toluene solution of sodium tert. amylate are introduced whilst maintaining the temperature between 15° and 22°C. The mixture is then left for 16 hours at ambient temperature. The mass is then cooled to -5°C and neutralised with 1350 ml of a 5% aqueous sulphuric acid solution. The reaction product is decanted and extracted with toluene; the toluene solutions are washed to neutrality and distilled. There is thus obtained a crude product which is rectified under reduced pressure to give 693 g of pure 3-carbethoxycyanomethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone. The principal bands of its infra-red spectrum are as follows: 3010, 1650, 720, 1750, 2260, 1410, 1250 cm⁻ ¹. NMR Spectrum: 0.96, 1.34, 4.26 and 5.40.

EXAMPLE 13

Into a 10 liter autoclave are introduced 677 g of 3-carbethoxycyanomethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone and 1354 ml of water. The autoclave is closed, a vacuum created therein (20 mm) and then heated to 195°C. The final interior pressure of the autoclave is 28 kg/cm². After cooling, extraction, washing, distillation of solvent and rectification there are obtained 261.8 g of 3-cyanomethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone. The product exhibits the following constants: b.p.₀.2 = 112°, n_(D) ¹⁵ = 1.4870.

The infra-red spectrum had principal bands at: 3020, 1650, 720, 1745, 2250, 1425 and 1410 cm⁻ ¹. NMR Spectrum: 0.96, 2.54 and 5.33.

EXAMPLE 14

Into a 2 liter flask fitted with a 1 meter adiabatic column provided with a metallic lining, are placed: 212 g of 3-cyanomethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone, 512 g of the glycoketal of methylethyl ketone and 2.1 g of para-toluenesulphonic acid. The mass is progressively heated in order to slowly distil the methyl ethyl ketone from the head of the column (temperature of the mass 120°-140°C; temperature of the vapour 77°-79°C). The operation lasts about 9 hours. The mass is then cooled, 10 g of dry sodium carbonate added thereto, stirred for a half-hour and the mass washed to neutrality after diluting with 200 ml of ethyl ether. After distillation of the solvent and rectification of the crude product, there is obtained 229.2 g of 3-cyanomethyl-1,1-ethylenedioxy-2-(cis-2-n-pentenyl)-cyclopentane. The product exhibits the following constants: b.p.₀.5 = 130°C, n_(D) ¹⁵ = 1.4862. The infra-red spectrum had principal bands at: 2240, 1650, 730, 1150, 1115 and 1040 cm⁻ ¹. NMR Spectrum: 0.95, 4.82, 5.36.

EXAMPLE 15

Into a 4 liter flask fitted with a stirrer, dropping funnel and vent, are introduced 229.2 g of 3-cyanomethyl-1,1-ethylenedioxy-2-(cis-2-n-pentenyl)-cyclopentane dissolved in 485 ml of anhydrous hexane. There is then added over 1 hour a solution of 180 g of diisobutylaluminium hydride in 485 ml of anhydrous hexane, while maintaining the temperature between 25° and 30°C. After addition of the hydride, the temperature of the mass is held at 30°C for 2 hours and it is then diluted with 970 ml of hexane. The whole of the solution is then added over 1 hour to 524 ml of a 10% aqueous solution of ammonium chloride while keeping the temperature in the region of 0°C. Into the so obtained mass, there is finally added, with constant stirring, a solution of 254 g acetic acid in 2134 ml of water. The hexane solutions are decanted, washed to neutrality and distilled; they yield a crude product which is rectified under 1 mm Hg. There is thus obtained 176.2 g of 1,1-ethylenedioxy-3-formylmethyl-2-(cis-2-n-pentenyl)-cyclopentane which can be represented by the formula ##SPC23##

The product exhibits the following constants: b.p.₀.5 = 120°, n_(D) ¹⁵ = 1.4862. It possesses a floral and green odor, reminiscent of lily-of-the-valley, and it also has an odour of champagne biscuits.

The infra-red spectrum has principal bands at: 1720, 2720, 1150, 1035, 945 and 730 cm⁻ ¹. NMR Spectrum 0.91, 4.82, 5.30 and 9.65.

EXAMPLE 16

A mixture of 47.6 g of 1,1-ethylenedioxy-3-formylmethyl-2-(cis-2-n-pentenyl)-cyclopentane, 80 ml of dioxane, 64 ml of water and 0.38 g para-toluenesulphonic acid is refluxed for 3 hours. It is then cooled, 120 ml of water added and extracted three times with 100 ml of benzene. The benzene solutions are washed to neutrality and concentrated under reduced pressure. There is obtained a crude product which is carefully rectified to yield 18.6 g of pure 3-formylmethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone exhibiting: b.p.₀.5 = 96°C. It can be represented by the formula ##SPC24##

It is characterized by a green fresh odour, reminiscent of Ivy, palmarosa and honeysuckle. The infra-red spectrum has principal bands at: 2720, 1720, 1735, 3010, 1650, 725 and 1405 cm⁻ ¹. NMR spectrum 0.92, 5.30 and 9.74.

EXAMPLE 17

Into a 1 liter flask equipped as described in Example 12, are introduced: 56.5 g of diisobutylaluminium hydride dissolved in 160 ml of anhydrous benzene. Maintaining the temperature in the region of 0°C, 31.5 g pyridine is added thereto over 20 min. Still at the same temperature there is then added 79 g of 1,1-ethylenedioxy-3-formylmethyl-2-(cis-2-n-pentenyl)-cyclopentane dissolved in 140 ml of anhydrous benzene over 30 minutes. The reaction mass is then brought to 30°C and held at that temperature for 2 hours; it is then diluted with 332 ml benzene, cooled to 0°C and then poured into 180 ml of an iced 10% aqueous solution of ammonium chloride. A solution of 79.5 g acetic acid in 660 ml of water is then added. The benzene solutions are decanted, washed to neutrality and distilled. The crude product so obtained is rectified under 0.5 mm Hg. There is thus obtained 54.8 g of 1,1-ethylenedioxy-3-hydroxyethyl-2-(cis-2-n-pentenyl)-cyclopentane. The product has the following constants: b.p.₀.2 = 125°C, n_(D) ¹⁵ = 1.4920.

The infra-red spectrum has principal bands at: 3440, 1150, 1040, 950, 3000, 1650 and 720 cm⁻ ¹.

NMR Spectrum: 0.94, 3.53, 3.80 and 5.32.

EXAMPLE 18

18 g of 1,1-ethylenedioxy-3-hydroxyethyl-2-(cis-2-n-pentenyl)-cyclopentane are mixed with 43.5 g of acetone and 0.145 g of paratoluenesulphonic acid. The mixture is brought to reflux during 1 hour, 0.25 ml of triethanolamine are then added thereto, the mixture concentrated on a waterbath under 30 mm Hg and the mass dissolved in 50 ml of benzene. The benzene solution, washed to neutrality and distilled under reduced pressure, yields a crude product which is rectified. There are thus obtained 12.3 g of 3-hydroxyethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone, which can be represented by the formula ##SPC25##

It is characterized by a spicy odour of green peppers evolving towards nutmeg with side notes of papaw fruit.

EXAMPLE 19

Into a 2 liter glass flask are introduced 86 g of absolute alcohol and 2.5 g of sodium. The solution is refluxed until the sodium has dissolved. To the cold solution is added slowly 83.6 g of ethylacetoacetate followed by 48.3 g of 2-(cis-2-n-pentenyl)-cyclopent-2-en-1-one. The solution is left at the ambient temperature for 3 1/2 days, neutralized with 6.9 g of acetic acid and poured into 300 ml of a 10% aqueous sodium chloride solution. After extraction of the organic phase with benzene, washing with water and distillation of the solvent on a water-bath; the product is distilled at 30 mm Hg to give 126 g of crude material which on rectification yields 10 g of 2-(cis-2-n-pentenyl)-3-(1-carbethoxy-2-isopropyl)-1-cyclopentanone.

EXAMPLE 20

Into a 1 liter autoclave, there are introduced: 54.7 g of 2-(cis-2-n-pentenyl)-3-(1-carbethoxy-2-oxopropyl)-1-cyclopentanone and 110 g of distilled water. The autoclave is evacuated and then rapidly heated to 150°C, which temperature is maintained for 3 hours. After cooling and decompression, the mass is extracted with benzene. The benzene solutions are washed with water distilled and rectified to yield 16.2 g of 2-(cis-2-n-pentenyl)-3-(2-oxopropyl)-1-cyclopentanone. Physical constants: b.p.₀.5 = 112°-113°C; n_(D) ¹⁵ = 1.4785. IR Spectrum: 1740, 1715, 1405, 1355, 1155, 970 and 1670 cm⁻ ¹. NMR Spectrum: 0.94, 2.08 and 5.34. The compound can be represented by the formula ##SPC26##

It possesses a jasmin-like odour a noble jasmin note, and also an odour of green, fruity, pea-pods and green apples.

The following examples A to E hereafter illustrate the use of the compounds of the invention in odoriferous compositions.

                  Example A                                                        ______________________________________                                         Parts by weight  Perfume with Hyacinth odour                                   ______________________________________                                         168              Bergamot peel oil extra                                       90               Lemon oil ordinary                                            36               Linalol                                                       27               Argeol                                                        18               Cinnamic alcohol synthetic                                    126              Phenylethyl alcohol                                           36               Phenylethyl acetate                                           72               Hydroxycitronellal                                            18               Terpineol                                                     18               Eugenol extra                                                 3.5              Galbanum oil                                                  9                Styrallyl acetate                                             63               Phenylacetaldehyde 50%                                        18               Styrax oil                                                    90               Benzyl salicylate                                             54               Hibiscolide                                                   36               Jasmin absolute                                               18               Vetiver Bourbon oil                                           9                Vanillin                                                      27               Tonka bean absolute                                           3.5              Tuberose absolute                                             60               3-Formylmethyl-2-n-pentyl-                                    1000             cyclopentanone                                                ______________________________________                                    

                  Example B                                                        ______________________________________                                         Parts by weight  Rose perfume                                                  ______________________________________                                         86               Linalyl acetate                                               143              Terpenyl acetate                                              86               Phenylethyl alcohol                                           28               Citronellol                                                   14               Cinnamic alcohol                                              28               Linalol                                                       7                Geraniol                                                      115              Terpineol                                                     215              Hydroxycitronellal                                            71               Styrax oil                                                    21               Methylionone                                                  21               Eugenol                                                       14               Phenylacetaldehyde                                            14               Hexylcinnamicaldehyde                                         21               Phenylacetaldehyde-dimethyl-                                                   acetal                                                        14               Sandalwood oil                                                28               Jasmin absolute                                               4                Oriental Rose oil                                             70               3-Formylmethyl-2-n-pentyl-                                    1000             cyclopentanone                                                ______________________________________                                    

                  Example C                                                        ______________________________________                                         Parts by weight                                                                            Perfume concentrate                                                ______________________________________                                         40          Phenylethyl alcohol                                                100         Bergamot peel oil extra                                            40          Lemon peel oil extra                                               50          Lavender oil Laragne 50%                                           10          Trimethyl undecanal, 10% in                                                    ethyl phthalate                                                    40          Ylang Ylang oil Nbe extra                                          20          Rose of May absolute                                               10          C. 11 aldehyde 100%, 10% in                                                    ethyl phthalate                                                    20          C. 12 aldehyde L 50%, 10% in                                                   ethyl phthalate                                                    30          Essence galbanum, 10% in                                                       ethyl phthalate                                                    60          Geraniol                                                           150         Hydroxycitronellal                                                 40          Jasmin absolute                                                    30          Guaiol acetate                                                     10          Forest moss absolute                                               30          Patchouly oil                                                      30          Coumarin                                                           40          Mixture of 1-ethoxy-4-(1-ethoxy-                                               vinyl)-3,3,5,5-tetramethylcyclo-                                               1-hexene and 4-(1-ethoxyvinyl)-                                                3,3,5,5-tetramethyl-cyclohexanone                                  20          Hibiscolide                                                        30          Musk ketone                                                        200         3-hydroxymethyl-2-n-pentyl-                                        1000        cyclopentanone                                                     ______________________________________                                    

                  Example D                                                        ______________________________________                                         Parts by weight                                                                            Space deodorant                                                    ______________________________________                                         75          Benzyl acetate                                                     25          Linalyl acetate                                                    65          Hydroxycitronellal                                                 200         Phenyl ethyl alcohol                                               50          Linalol                                                            100         Terpineol                                                          100         Geraniol                                                           25          Ylang-Ylang third                                                  5           Methyl anthranylate                                                5           Indolene, 1% in ethyl phthalate                                    25          Iso eugenol                                                        15          Anisyl aldehyde                                                    50          Styrallyl acetate, 10%                                             25          Santalol                                                           10          Geranium Bourbon oil                                               10          Musk ambrette                                                      15          Musk ketone                                                        200         3-Cyanomethyl-2-n-pentyl-                                          1000        cyclopentanone                                                     ______________________________________                                    

                  Example E                                                        ______________________________________                                         Parts by weight                                                                               Toilet water                                                    ______________________________________                                         20             Linalyl acetate                                                 50             Lavender oil Laragne 50%                                        70             Linalol                                                         50             Lemon peel oil extra                                            50             Mandarin oil extra                                              20             Menthol                                                         10             Ylang-Ylang Nossi-Be extra                                      100            Hydroxycitronellal                                              20             Clary sage oil                                                  60             Vetiveryl acetate                                               30             Caryophyllenyl acetate                                          30             East Indien Sandalwood oil                                      60             Methylionone                                                    60             Amyl salicylate                                                 80             Benzyl salicylate                                               20             Patchouly oil, Grasse                                           30             Coumarin                                                        70             Resinoid benzoin                                                20             Musk ketone                                                     150            1,1-Ethylenedioxy-3-formyl-                                     1000           methyl-2-n-pentyl-cyclopentane                                  ______________________________________                                     

What is claimed is:
 1. Cyclopentanone derivatives of the formula ##SPC27##in which R represents a hydrocarbon group of 3 to 7 carbon atoms, X represents a formyl, hydroxymethyl, lower alkoxymethyl, or lower alkylcarbonyl group and Y represents an oxo or ketal group,with the proviso that R does not represent an n-pentyl group when, simultaneously, X represents a methylcarbonyl group and Y represents an oxo group.
 2. Compounds according to claim 1, wherein Y represents an oxo group.
 3. Compounds according to claim 1, wherein Y represents a cyclic ketal group containing 2 or 3 carbon atoms.
 4. Compounds according to claim 3, wherein Y represents an ethylenedioxy group.
 5. Compounds according to claim 1, wherein Y represents the group ##EQU2## in which R¹ and R² represent lower alkyl groups containing up to 4 carbon atoms.
 6. Compounds according to claim 5, wherein R¹ and R² each represent a methyl or ethyl group.
 7. Compounds according to claim 1, wherein R repesents an alkyl group of 3 to 7 carbon atoms.
 8. Compounds according to claim 1, wherein R represents an n-pentyl group.
 9. A compound according to claim 1, in which said compound is 1,1-ethylenedioxy-3-formylmethyl-2-n-pentylcyclopentane.
 10. A compound according to claim 1, in which said compound is 3-formylmethyl-2-n-pentyl-1-cyclopentanone.
 11. A compound according to claim 1, in which said compound is 1,1-ethylenedioxy-3-hydroxyethyl-2-n-pentylcyclopentane.
 12. A compound according to claim 1, in which said compound is 3-hydroxyethyl-2-n-pentyl-1-cyclopentanone.
 13. Compounds according to claim 1, wherein R represents a 2-n-pentenyl group.
 14. A compound according to claim 1, in which said compound is 2-(Cis-2-n-pentenyl)-3-(2-oxopropyl)-1-cyclopentanone.
 15. A compound according to claim 1, in which said compound is 1,1-Ethylenedioxy-3-formyl-methyl-2-(cis-2-n-pentenyl)-cyclopentane.
 16. A compound according to claim 1, in which said compound is 3-Formylmethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone.
 17. A compound according to claim 1, in which said compound is 3-Hydroxyethyl-2-(cis-2-n-pentenyl)-1-cyclopentanone.
 18. A compound according to claim 1, in which said compound is 3-acetoxyethyl-2-n-pentyl-1-cyclopentanone. 